I’ve got a DSL connection, which normally is pretty fast. It seems that whenever I try to download something from the net, I start out at a nice 122kb/s transfer rate, but inevitably it always slows down to somewhere around 60-70kb/s. A few times it’s turtled along at 18! Why the sudden slowdown?
The reason the speed is fast at first is that some of the data is stored in a buffer. Once that buffer is emtied then the download speed drops down to its real-time value. This also happens to me on an ordinary dial-up line , dropping from 9 down to 2 kbits.sec.
Do you have verizon dsl ( old name bellatlantic infospeed).
If so your limit is apx 60 kB/s (60kB/s*8 bits/Byte = 480 kb/s + overhead gives you the advertized 640 kb/s). I have that service. My guess is that it is either the buffer or more likely the download speed before you hit the cap.
Think of it this way, your dsl is capable of 1.5mb/s (1500 kb/s) but you are only paying for service of 640 kb/s. before you are downloading you are way under the limit then you start downloading to your lines capacity. your isp sees the increase of bandwidth and puts limits on it - slowing you connection to your cap. the slow down lowere you to an average of 60 kb/s